Fuel injection for diesel engines



p 11, 1956 H. SEEGELKEN 2,762,347

FUEL INJECTION FOR DIESEL ENGINES Filed March 15, 1954 INVEN Herman/1Jegge BY FUEL INJECTION FOR DIESEL ENGINES Hermann Seegelken, Numberg,Germany, assignor to Maschmenfabrik Augsburg-Numberg, A. G., Numberg,Germany Application March 15, 1954, Serial N 0. 416,372 Claims priority,application Germany March 24, 1953 7 Claims. (Cl. 12332) This inventionrelates to injection of fuel and air into the combustion chamber of adiesel engine. In particular, the invention is directed to an improvedmethod of injecting the fuel and air into the combustion chamber so thatan improved fuel air mixture is obtained.

In the co-pending application of Meurer et al., Serial No. 480,432,filed 7 January 1952, for Operation of Internal Combustion Engines,which is a continuation-in-part of the earlier application for InjectionSystem for Internal Combustion Engines, Serial No. 325,316, filedDecember 11, 1953, now abandoned, a disclosure is made of injecting fuelagainst the wall of a combustion chamber located in the piston head, andthen wiping away and vaporizing this film layer with the intake air. Itis also disclosed that an improved injection of the fuel into thecombustion chamber can be obtained if the axis of the combustion chamberis displaced with respect to the axis of the piston.

The objects of the instant invention are to improve upon the manner ofinjecting the fuel and air into the combustion chamber, and to modifythe combustion chamber so that a more effective vaporizing of the filmby the intake air is achieved.

In general these objects are achieved by constructing the combustionchamber in the piston head with a surface formed by the revolution of acurved line, said chamber having its axis displaced from the piston axisas disclosed in said co-pending application. The upper edge of thechamber is cut away to form an air passageway which extends through thetop edge into and along and then merges with the wall of the combustionchamber in a stream-lined manner. The fuel is projected in one or morejets onto the wall of this pasageway either directly before or after thepoint where the passageway merges with the wall of the combustionchamber. By so doing the greater portion of the intake air is held to arelatively closed path which is concentrated upon, and wipes over theliquid film deposited on the wall of the passageway of the combustionchamber. The direction of the intake air is as tangential to thecombustion chamber wall as possible.

Thus, the amount of intake air entering the passageway is thereforegreater than would enter the combustion chamber with the passagewayomitted. The amount of air passing over the film of fuel is thereforeincreased so that the film is rapidly vaporized. In addition to thisintake passageway, a second pocket-like chamber may be formed in thewall of the combustion chamber beyond the portion of the wall adapted tobe coated with the film of fuel. This second pocket-like chamber servesto further increase the amount of air flowing through the intakepassageway and also to assist in discharging the gas stream from thecombustion chamber after the gases have been ignited during thecompression stroke.

The means by which the objects of the invention are obtained. aredescribed more fully with respect to the accompanying drawings, inwhich:

Figure 1 is a cross-sectional view through a piston con- United StatesPatent Patented Sept. 11, 1956 structed according to the invention, andindicating the piston of the fuel nozzle and jets of fuel;

Figure 2 is a top plan view of the piston shown in Figure 1, theinjection nozzle being omitted;

Figure 2a is a cross-sectional view on the line 2a-2a of Figure 2.

Figure 3 is a cross-sectional view of a modified form of piston, and

Figure 4 is a top plan view of this modified form.

In Figure 1 the piston 2 has a combustion chamber'4 formed in the headof the piston, this chamber having a wall shaped by a curved line ofrevolution. The upper end of the chamber 4 connects with the surface ofthe piston through a cylindrical wall 6 having an upper edge 8. The axis10 of chamber 4 is offset from the axis 12 of piston 2.

The upper edge 8 of the combustion chamber is inter rupted by arelatively deep notch 14 which continues into a passageway 16, saidpassageway extending through the cylindrical wall 6 and being continuedinto a pocketlike chamber formed in the wall of the combustion chamber4, and which passageway decreases in depth and gradually merges into thecontour of said wall in the direction of air rotation. For example,passageway 16 extends over about of the circumference of said chamber,and has its upper and lower portions edgelessly merged with the wall ofsaid chamber. The area and extent of the passageway varies in accordancewith the particular piston design, but its function remains the sameregardless.

Fuel from injection nozzle 18 is directed in the form of one or morejets 20 and 22 into the fuel chamber, these jets being preferablytangentially impacted on the wall of the chamber or said pasagewayadjacent the point where the passageway 16 merges with the wall of thecombustion chamber 4. That is to say a film of fuel is formed in thepassageway immediately prior to its mergence with the wall of chamber 4or immediately thereafter, or both. Intake air is given a circularmotion as described in said co-pending application and this rotarymotion is concentrated into a stream entering the combustion chamberthrough notch 14 in the direction of arrow 26 and tangentially directedover the fuel film deposited on the wall of the chamber. This air isswirled about in the chamber during the compression stroke and afterignition is dis.- charged from the chamber in the direction of the arrow28 whereby the air passes over the fuel film one or more times. The fuelfilm is therefore thoroughly vaporized and mixed with the air to formthe combustion gas.

As shown in Figures 3 and 4, another pocket-like chamber 30 can beprovided immediately behind notch 14 and pocket 16 in the direction ofair rotation, this pocket being stream-lined in the same direction fromthe wall of the chamber to the outlet notch 32 in upper edge 8. Thecombustion products after ignition are discharged through notch 32, butbefore ignition the air passes over the fuel film one or more times tothoroughly vaporize the same, and during the discharging period thegases pass over the areas on which the fuel was deposited to vaporizeand wipe away any remaining traces of the fuel.

The use of the pocket 30 increases the velocity of the air and the gasesduring the discharging period near the mediately after it entersthechamber, while the greater portion of the air would not reach the filmlayer, or

with the vaporized fuel until a relatively long time after thecompletion of the intake phase. In said co-pending application it hasbeen described how this can be improved upon by directing the intake airinto a closed path which passes through the fuel injection stream andbrushes over the fuel deposited on the compression chamber wall, andthat this closed ,path can be achieved by providing a channel or duct inthe piston head which terminates tangentially with respect to the wallof the combustion chamber. The combustion products are exhausted in asimilar manner. The present invention further improves upon thevaporization of the fuel by concentrating substantially all of theintake air 'on the deposited fuel film, this concentration beingobtained by the passageways formed in the wall of the combustionchambers. this way a larger portion of the air rotating about thecylinder axis and the air displaced from the cylinder space during thecompression stroke flows from the sharp depression for-med by the notchin edge 8 through the enlargement into the combustion chamber.Consequently, the amount of air entering the combustion-chamber at thisenlargement is increased, and therefore the velocity of the air over'the fuel film is increased to further the rapid vaporization of thefuel. his clear that the invention is not limited to the basic shape ofthe combustion chamber shown in the drawings, but may be applied to thevarious forms of combustion chamber shown in said aforementionedco-penrli-ng application.

Having now described the means by which the objects of the invention areobtained, I claim:

1. In an internal combustion engine having a cylinder, a piston in saidcylir'ider, 'a combustion chamber in the head of said piston having ashape formed by the revolution of a curved line, means for injectingfuel upon the wall of said chamber in the form of thin film, and furthermeans to impart to the intake air "a rotary motion about the cylinderaxis in the direction of the fuel jets thereby vaporizing wall-depositedfuel with the air entering and circulating in the combustion chamber,air directing means comprising a notch which continues into a passagewayboth formed in the wall of the combustion chamber and graduallyincreasing radially with respect to the cylinder axis from near thebottom of the combustion chamber up to the opening of said chamber, saidnotch forming an abrupt enlargement'of the opening into said chamber andsaid passageway'extending from said notch in the direction of therotating air and then gradually diminishing in lateral extension'unti'litmerge's with the wall of said combustion chamber, whereby the greaterpart of the air "rotating in the cylinder is displaced during the pistoncompression stroke and flows through said notch into said passageway,and said fuel injection means further comprising means for injectingfuel in said chamber in the direction of the flow of air therein and asa film of fuel deposited on said chamber wall adjacent the merger of'said passageway with the contour of said chamber wall and in the pathof the air flowing through said passageway.

2. In an internal combustion engine having a cylinder, a piston in saidcylinder, a combustion chamber in the head of said piston having a shapeformed by the revolution of a curved line, means for injecting fuel uponthe wall of said chamber in the form of thin film, and further means toimpart to the intake air a rotary motion about the cylinder axis in thedirection of the fuel jets thereby vaporizing wall-deposited fuel withthe air entering and circulating in the combustion chamber, airdirecting means comprising a notch which continues into a'passagewayboth formed in the wall of the combustion chamber and graduallyincreasing radially with respect to the cylinder axis from near thebottom of the combustion chamber up to the opening of said chamher, said'notch forming an abrupt enlargement of the opening into said chamberand said passageway extending from said notch in the direction of therotating air and then gradually diminishing in lateral extension untilit merges with the wall of said combustion chamber, whereby the greaterpart of the air rotating in the cylinder is displaced during the pistoncompression stroke and flows through said notch into said passageway,and said fuel injection means further comprising means for injecting thefuel onto the wall of said passageway in the direction of the how of airtherein and as a film of fuel deposited on said wall before the pointwhere said passageway merges into the wall of the combustion chamber.

3. In an internal combustion engine having a cylinder, a piston in saidcylinder, a combustion chamber in the head of said piston having a shapeformed by the revolution of a curved line, means for injecting fuel uponthe wall of said chamber in the form of thin film, and furthe: means toimpart to the intake air a rotary motion about the cylinder axis in thedirection of the fuel jets thereby vaporizing wall-deposited fuel withthe air entering and circulating in the combustion chamber, airdirecting means comprising a notch which continues into a passagewayboth formed in the wall of the combustion chamber and graduallyincreasing radially with respect to the cylinder axis from near thebottom of the combustion chamber up to the opening of said chamber, saidnotch forming an abrupt enlargement of the opening into said chamber andsaid passageway extending from said notch in. the direction of therotating air and then gradually diminishing in lateral extension untilit merges with the wall of said combustion chamber, whereby the greaterpart of the air rotating in the cylinder is displaced during the pistoncompression stroke andflows through said notch into said passageway andsaid fuel injection means further comprising means for injecting thefuel onto the wall of said chamber in the direction of the how of airtherein and as a film of fuel deposited on said wall immediately afterthe point where said passageway merges into the wallet the combustionchamber.

4. In an internal combustion engine as in claim 1, said piston furthercomprising a second passageway communicating with a second notch in thechamber opening on a subsequent part of the combustion chamber in thedirection of the flow of air and following the deposited film 'of fueland forming an exhaust path for ignited gases.

5. In an internal combustion engine as in claim 4, said secondpassageway beginning in the direction of the flow of air immediatelyadjacent the merger of the first mentioned passageway and said wall andbeing streamlined :to said second notch to form a substantially mirrorimage of the first named passageway and notch. v

6. -In an internal combustion chamber as in claim 5, the vertical axisof said chamber being offset with respect to the vertical axis of saidpiston, and said second notch being on the side of the piston the moreclose 'to said piston axis.

7. :In an internal combustion engine as in claim 1, the vertical axis ofsaid chamber being offset from the vertical axis of said piston, andsaid -notch being on the side ofsaid piston the more distant from saidpiston axis.

References Cited in the tilt: of this patent UNITED STATES PATENTS;1,943,49s Thomas Jan. 16, 1934 2,514,730 Sonderegger July ll, 0

2,620,781 Petersen Dec. '9, 1952 FOREIGN PATENTS 907,677 France Mar. 19,1946 952,636 France Nov. '21, 1949 643,619 Great Britain Sept. 20, 1950OTHER REFERENCES Serial No. 25L007, Wiebicke (A. P. Ct), published May11, 1943.

